81600000 has 240 divisors, whose sum is σ = 287700336. Its totient is φ = 20480000.

The previous prime is 81599993. The next prime is 81600023. The reversal of 81600000 is 618.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4799992 + ... + 4800008.

Almost surely, 2^81600000 is an apocalyptic number.

81600000 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81600000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (143850168).

81600000 is an abundant number, since it is smaller than the sum of its proper divisors (206100336).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81600000 is an frugal number, since it uses more digits than its factorization.

81600000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63 (or 27 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 81600000 is about 9033.2718325090. The cubic root of 81600000 is about 433.7405770500.

Adding to 81600000 its reverse (618), we get a palindrome (81600618).

The spelling of 81600000 in words is "eighty-one million, six hundred thousand".